Abstract: In a method for a model-based determination of a temperature distribution of an exhaust gas post-treatment unit, a differentiation is made between steady operating states and non-steady operating states by taking into account the axial and the radial temperature distribution, and, on the basis of virtual segmentation of the post-treatment unit, in particular the radial heat transfer to the surroundings is taken into account in the model-based determination for steady operating states, and for non-steady operating states the heat transfer from the exhaust gas which flows axially through the post-treatment unit to the segments is taken into account by a heat transfer coefficient k.

Abstract: The invention relates to a supply system for a medium, in particular for an exhaust-gas purification apparatus for the treatment of exhaust gases of an internal combustion engine, having a storage vessel for the medium, having a dosing device for dosing the medium, and having a provision line which comprises a feed line for the supply of the medium to the dosing device and a return line for returning the medium from the dosing device into the storage vessel. Flow can pass through the dosing device from a feed port to a return port of the dosing device. The provision line comprises an additional fluid connection between the feed line and the return line. The additional fluid connection opens out into the feed line upstream of the feed port of the dosing device and opens out into the return line downstream of the return port of the dosing device.

Abstract: Reciprocating-piston internal combustion engines having different power outputs are to be equipped simply, reliably and inexpensively with a device for the selective catalytic reduction of the exhaust gases having an SCR module for a reciprocating-piston internal combustion engine, comprising a housing and/or a frame, an exhaust-gas section which delimits a flow duct for guiding through exhaust gas, having an inlet opening for introducing the exhaust gas and an outlet opening for discharging the exhaust gas, an SCR catalytic converter which is arranged inside the flow duct, at least one injection element for adding a reducing agent, for example ammonia or a urea solution, to the exhaust gas which is guided through the flow duct. This problem is solved by virtue of the fact that the SCR module comprises at least one delivery device (13) for feeding the reducing agent to the injection element at a predetermined pressure.

Abstract: The invention relates to a supply system for a medium, in particular for an exhaust-gas purification apparatus for the treatment of exhaust gases of an internal combustion engine, having a storage vessel for the medium, having a dosing device for dosing the medium, and having a provision line which comprises a feed line for the supply of the medium to the dosing device and a return line for returning the medium from the dosing device into the storage vessel. Flow can pass through the dosing device from a feed port to a return port of the dosing device. The provision line comprises an additional fluid connection between the feed line and the return line. The additional fluid connection opens out into the feed line upstream of the feed port of the dosing device and opens out into the return line downstream of the return port of the dosing device.

Abstract: Reciprocating-piston internal combustion engines having different power outputs are to be equipped simply, reliably and inexpensively with a device for the selective catalytic reduction of the exhaust gases having an SCR module for a reciprocating-piston internal combustion engine, comprising a housing and/or a frame, an exhaust-gas section which delimits a flow duct for guiding through exhaust gas, having an inlet opening for introducing the exhaust gas and an outlet opening for discharging the exhaust gas, an SCR catalytic converter which is arranged inside the flow duct, at least one injection element for adding a reducing agent, for example ammonia or a urea solution, to the exhaust gas which is guided through the flow duct. This problem is solved by virtue of the fact that the SCR module comprises at least one delivery device (13) for feeding the reducing agent to the injection element at a predetermined pressure.

Abstract: In a method for a model-based determination of a temperature distribution of an exhaust gas post-treatment unit, a differentiation is made between steady operating states and non-steady operating states by taking into account the axial and the radial temperature distribution, and, on the basis of virtual segmentation of the post-treatment unit, in particular the radial heat transfer to the surroundings is taken into account in the model-based determination for steady operating states, and for non-steady operating states the heat transfer from the exhaust gas which flows axially through the post-treatment unit to the segments is taken into account by a heat transfer coefficient k.